What Is an Adverse Reaction?

Adverse reaction refers to the occurrence of adverse reactions that are not related to the purpose of treatment during the process of preventing, diagnosing or treating diseases by applying drugs according to normal usage and dosage. Its specific occurrence condition is to use the medicine in the normal dosage and normal usage, and exclude the reactions caused by drug abuse, excessive misuse, use of drugs in accordance with prescribed methods, and quality problems.

Chinese name: Adverse reactions
Foreign name: Adverse reaction

Include: Side effects, etc.
Classification: A, B two categories
severity: Mild, moderate, severe

Definition of adverse reactions

Any reaction that is inconsistent with the purpose of the medication and causes discomfort or pain to the patient after the medication is collectively referred to as adverse reaction. Adverse effects of drugs include sideeffects, toxicreactions, allergicreactions, aftereffects, secondaryeffects, idiosyncraticreactions and "three causes" (carcinogenicity) carcinogenesis, teratogenesis, mutagenesis). Generally predictable, but some are inevitable and some are difficult to recover.

Sequelae of adverse drug reactions

Refers to the biological effect after discontinuation, such as taking barbiturates, the hangover phenomenon the next day, which can disappear after discontinuation. Cochlear nerve damage caused by aminoglycoside antibiotics is difficult to recover and can become permanent deafness. An allergic reaction to an abnormal immune response that occurs when the drug stimulates the body. The drug binds to a polymer carrier protein in the body to form an antigen, which stimulates the body to produce antibodies, and the drug enters the body again to cause an antigen-antibody reaction, causing an allergic disease.

Adverse reaction

A small number of people will have reactions unrelated to pharmacological effects after taking the medicine. Most of them are due to abnormal biochemical mechanisms of the individual, such as the lack of a dependent larynx formed by a certain drug metabolism enzyme, the body cannot maintain normal physiological functions after drug withdrawal, and the withdrawal syndrome appears, which is sometimes severe, and convulsions can even occur.

Teratogenic effects of adverse drug reactions

During pregnancy, especially during the first three months of fetal organogenesis, certain drugs can affect the fetus and cause congenital malformations.

Carcinogenic effects of adverse drug reactions

Drugs with carcinogenic effects are called carcinogens, and many chemicals belong to this category.

Mutagenic effects of adverse drug reactions

Sudden mutations and chromosomal abnormalities in the composition of genetic factors DNA can be called mutations. In a short period of time, the mutagen causes significant biological mutations, such as teratogens or tumors, through the body.

Classification of adverse reactions

Adverse drug reactions are divided into two categories, A and B. Type A reactions are mainly toxic and side effects, while Type B reactions are specific or atopic. A few idiosyncratic individuals may have extremely sensitive or very insensitive reactions to one or more drugs. Idiopathic means "characteristics of a person; peculiar susceptibility; strange response". Type B reactions can be further divided into genetic pharmacological adverse reactions and drug allergies.

A Adverse reactions

Type A reaction is also called dose-related adverse reaction. It is an extension and development of conventional pharmacological effects of drugs. Whether it occurs in the body is closely related to the level of the drug (or the size of the dose).

[Excessive effect]

Drugs have an effect on the human body, which is generally a therapeutic effect, that is, to moderately adjust the function to make it normal, but sometimes there are too strong effects that cause adverse reactions.

[side effect]

When a drug has multiple effects, all effects other than therapeutic effects can be considered side effects. The side effects are often transient, the therapeutic effect of the drug disappears, and the response subsides, but sometimes it can cause more serious consequences.

[Toxic reaction]

Toxicity and side effects are difficult to distinguish, and habits depend on the severity of the reaction. In general, toxicity refers to reactions that can cause certain functional or organic damage. Some of these reactions can gradually recover after stopping the drug, but often cause some irreversible damage and never go back for life.

[First dose effect]

When some drugs are applied, the body's effects on the drug have not been adapted, so it can cause a strong response. If the drug is used at the beginning, it often causes excessive effects. For such drugs, it should be started from a small dose Gradually increase the amount to the usual amount, so that the body gradually adapts.

[Secondary reaction]

The secondary reaction is not the effect of the drug itself, but the response induced by the effect of the drug. For example, broad-spectrum antibiotics can cause flora imbalance and cause certain vitamin deficiencies and secondary infections;

[Withdrawal syndrome]

Or called withdrawal. Due to the long-term application of the drug, the body's effect on the drug has been adapted, and once the drug is discontinued, the body will be in a state of non-adaptation. The main manifestation is the rebound of symptoms.

B Adverse reactions

[Genetic pharmacological adverse reactions]

Many drugs are metabolized in the liver. In most cases, the effect of drug metabolites is lower than that of the original drug, and the toxic and side effects are correspondingly reduced. Different drugs have different metabolic pathways. Some drugs are oxidized, some are reduced, some are hydrolyzed, some are nucleosides, and some are combined with glucuronic acid. These metabolic reactions are performed under the action of corresponding enzymes. The metabolic process will be blocked, resulting in the accumulation of the original drug in the body, and the effect will increase accordingly. Many factors can affect the amount of enzymes and their functions in the body, but this type of reaction excludes the effects of the above conditions, and specifically refers to the poor metabolism of drugs due to genetic inheritance.

[Drug allergy]

Drug allergic reactions are abnormal immune reactions between foreign antigenic substances and antibodies in the body. When foreign antigens enter the body, sensitize the lymphocytes or humoral immune system, the body is in the sensitized state, and when the body contacts the same allergen again, the antigen reacts with antibodies, causing some degree of tissue damage or function obstacle.

[Clinical manifestations of allergic reactions]

The clinical manifestations of allergic reactions include skin reactions and systemic reactions.

Skin reactions: manifested as various drug rashes, with urticaria type, measles type, and eczema skin types being common, and some drugs can form fixed drug rashes.

Systemic reactions: Allergic reactions can damage various systems, such as blood-like reactions, serum-like reactions, lupus-like reactions, hepatitis-like reactions and damage to the cardiovascular, nervous system, kidney, respiratory tract and other parts, and anaphylactic shock.

Adverse drug reactions

Adverse drug reaction refers to the unintentional or accidental adverse reaction that occurs in the human body when receiving normal doses of drugs during the period of disease prevention, diagnosis, treatment or recovery of human function.

In contrast to adverse drug events, the causal relationship between adverse drug reactions and drugs is judged by the medical experts responsible for reporting or checking. If a response report comes from a medical expert, it is usually implied that the reaction is an adverse drug reaction, unless the medical expert explicitly states that the reaction is not causally related to the drug.

Drugs are like a double-edged sword. While having a therapeutic effect, there must be adverse reactions. Therefore, a drug that has been notified of an adverse reaction does not indicate an unqualified drug, and it should not be compared with "poison", "counterfeit drug", "inferior drug", and "unusable". At present, Guangdong Province has launched a system for reporting adverse drug reactions. Chen Taichang said that the reporting of adverse drug events is to remind drug manufacturers, operating companies, medical institutions and the general public to pay attention to potential safety hazards in drugs and to avoid serious drugs as much as possible. The recurrence of adverse reactions thus sets up an effective barrier to ensure the safety of the public in medication.

At present, people do not understand the adverse reactions of medicines, thinking that the newer drugs have better curative effects, and ignore the adverse reactions. In fact, the number of pre-market clinical trials of new drugs is limited to about 500-3000 people. In most cases, special populations such as the elderly, pregnant women, and children are excluded. Therefore, some rare adverse reactions, late-onset reactions, and adverse reactions that occur in special populations Difficult to find. The problem with some drugs is that they can only be found after a longer period of use in a larger population. Therefore, we should be alert to the adverse reactions of drugs, especially the adverse reactions of new drugs.

Adverse Drug Reaction (ADR) (see ICH-E2D)

Adverse drug reactions, as established by regional regulations, guidance, and practices, concern noxious and unintended responses to a medicinal product.

The phrase "response to a medicinal product" means that acausal relationship between a medicinal product and an adverse event is at least a reasonable possibility (refer to the ICH-E2A guideline).

A reaction, in contrast to an event, is characterized by the fact that a causal relationship between the drug and the occurrence is suspected. For regulatory reporting purposes, if an event is spontaneously reported, even if the relationship is unknown or unstated, it meets the definition of an adverse drug reaction.

Grade of adverse reaction

Grade of severity of adverse drug reactions:

1) Mild: Refers to a mild reaction or disease. The symptoms do not develop and generally do not require treatment.

2) Moderate: Significant adverse reactions and moderate damage to important organs or system functions.

3) Severe: refers to the serious damage to important organs or systems, which causes disability or shortens or endangers life.

Serious reaction

Cause death

2. Carcinogenic, teratogenic, mutation (genetic mutation);

3. Danger to life and can cause permanent or significant disability;

4. Permanent damage to organ function;

5. Resulting in hospitalization or extended hospital stay.

Drugs related to adverse reactions

Adverse drug reactions that caused concern in previous years

1. Contec (compound preparation)

2. Bestine (Cilivastatin)

3. Nuomei Pavilion (Sibutramine)

4. Astemizole (asmidazole)

5. Sisabyl (Pribes)

Phenylpropanolamine hydrochloride in Contec can cause hemorrhagic stroke.

Bestine can cause rhabdomyolysis, especially when used with gemfiprozil, which can lead to severe renal failure and death.

Sibutramine can cause life-threatening hypertension.

When used in combination with other drugs, zismin and cisapride often accumulate in the human body due to the effects of other drugs, leading to cardiotoxicity, leading torsional ventricular tachycardia, and severe death.

Comments on adverse reactions

"It is a drug with three levels of toxicity." Adverse drug reactions refer to unacceptable or unexpected adverse reactions in the normal usage and dosage of qualified drugs that have nothing to do with the purpose of the drug. Many patients in life are frightened by a long list of adverse drug reactions in the instructions. They think, "Where are you treating the disease, and you are clearly committing suicide?" Only dare to use it when it is too little. In fact, the occurrence of adverse reactions to medicines is related to the patient's physical condition, age, genetic factors, living habits, and other factors. It is part of the experience of using drugs accumulated in practice. Now most of the adverse reactions in detail are actually drugs. Both have long-term clinical practice support, or are supported by corresponding literature or case reports. The instructions serve as statutory documents, which provide complete information on adverse drug reactions, and fulfilling the obligation to inform is its basic function. Therefore, since no drug is absolutely safe, and the absence of written information on adverse reactions does not mean that no adverse reactions have occurred, then for clinicians and pharmacists, it is generally more trustworthy for the drug manufacturers' instructions with detailed adverse reaction information, because the detailed information Instead, it puts a lock on the safety of clinical treatment. So the ostrich method of burying its head in the sand is not desirable. In addition, most of the common adverse reactions do not affect the treatment and your safety. You only need to strengthen observation. At the same time, adverse reactions do not occur for everyone, and the chance of serious adverse reactions is even harder than your lottery. ^[1] .

Whether in medical practice or in real life, it is prudent to give medicines to expectant mothers and new mothers. There is usually a simple description in the instructions, such as "use with caution for pregnant women", "prohibition for lactating women", etc. Generally speaking, pre-marketing trials have no data on pregnant women, and most of the instructions mention The information is either from subsequent clinical reports or speculation from animal experiments, but in a responsible manner to mothers and children, it is recommended that if you encounter such problems, you must consult a professional doctor before proceeding Treatment must not be self-assertive.